Parks later paid tribute to the effect that her experience in Clark's workshops at Highlander had on her. "I am always very much respectful and very much in awe of the presence of Clark because her life story makes the effort I have made very minute. I only hope that there is a possible chance that some of her great courage and dignity and wisdom has rubbed off on me."
Highlander thrived, and Clark developed a strategy of recruiting attendees and training them to go back to their communities and start their own citizenship schools. She called the effect "like a pebble thrown into a mill pond." But the school also came under intense scrutiny and attack from enemies of integration. The FBI had been monitoring it for a long time, and neighbors had tried to shut it down, but it as not until July 31, 1959, that the state used force to end it.
That Friday night, as the group was watching a documentary after a long day and celebratory dinner, 18 armed law enforcement officers burst into the hall. They raided the entire school and took then-61-year-old Clark and two others to jail. At 2:30 a.m., a Highlander teacher posted the $500 bail needed for her release. As a result of this raid, the court judge revoked Highlander's charter on the grounds that it had "permitted integration in its school work."
Horton and Clark had already developed a contingency plan: They joined forces with Martin Luther King Jr.'s Southern Christian Leadership Conference (SCLC). King, who had visited Highlander the year after he rose to fame in the Montgomery bus boycott, saw the potential synergy. The SCLC records state: "The CEP [Citizenship Education Program] was established in 1960 when Septima P. Clark, a literacy teacher at the Highlander Folk School, convinced Martin Luther King Jr. that literacy training and political education would spur voter registration among African-Americans in the South."